1. Field of the Invention:
The present invention relates to a supporting metal fitting for use in installing ducts, pipes, instruments, air conditioners, etc. on a ceiling of a building and the like.
2. Prior Art:
Conventionally, when ducts, pipes, instruments air conditioners, etc. are installed inside a building, there is employed a method comprising the steps of previously preparing a double beam arrangement for use on a portion adjacent to the ceiling of the building, mounting metal fittings on the double beam arrangement and suspending such ducts, etc. by the metal fittings mounted on the double beam arrangement.
The conventional double beam arrangement comprises two L-type beams (L-beams), each having first and second sides extending in an angled relationship to each other as illustrated in FIGS. 1 and 2.
In the double beam arrangement the L-beams, or as generically referred to hereinafter, double beams a, are disposed in a back to back spaced apart relationship with a gap c provided therebetween so that a lifting metal fitting b can be inserted into the gap c. The gap c is defined, as illustrated in FIG. 1, by welding a spacer d formed of a round rod to the angles a at a given interval therebetween. The gap c is also defined by interposing a collar e between the angles a and inserting a bolt f into the angles a and the collar e so as to fasten them by a nut g.
However, since it takes time and labor for providing the gap by welding or fastening by the bolt and the nut, and various sizes of the angles should be manufactured depending on a hanging load, there is such a drawback that the custody and the maintenance of the angles are troublesome.
If they were cut to a necessary length at a building site, remaining portions of angles after cutting can not be used for other purposes, which renders the angles to be wasteful.